This is a study of the effect of Ca channel blockade with nifedipine and diltiazem in normals and patients with essential hypertension. Results show that increased pressor sensitivity of the blood pressure to angiotensinII (A-II) on a high Na diet is largely blocked by nifedipine and diltiazem, while increased aldosterone response to A-II on a low Na diet is partially blocked by both drugs. Similiar studies are planned with ACTH.